ABSTRACT
Objective: To explore the association between serum levels of osteopontin (OPN) and systolic pulmonary artery pressure (sPAP) in healthy men following acute high altitude exposure. Methods: According to the inclusion and exclusion criteria, this observational study included 94 male subjects (aged from 18 to 30 years, dwelling in lowland<500 m) who ascended to Litang (4 100 m) from Chongqing (400 m) by bus with a stair-like journey within 7 days in June 2013. Data including basic information, OPN, superoxide dismutase (SOD), and malondialdehyde (MDA) and echocardiographic derived sPAP were collected within 48 hours before ascent and within 2-7 hours after arrival. Accordingly, subjects were divided into 3 groups based on the tertiles of sPAP after acute high altitude exposure: low sPAP group (26.8-32.3 mmHg (1 mmHg=0.133 kPa)) (n=31), middle sPAP group (32.4-37.4 mmHg) (n=32) and high sPAP group (37.5-55.6 mmHg) (n=31). Associations of serum OPN and SOD levels with sPAP were analysed by univariate and multivariate linear regression analysis. Results: After acute high altitude exposure, the levels of sPAP were significantly increased (P<0.001). There were no differences in age, height, weight, body mass index, percent of Han nationality and smoking among 3 subgroups. However, following acute high altitude exposure, the levels of heart rate, systolic and diastolic blood pressure elevated (all P<0.05), whereas the levels of oxygen saturation were reduced in the total subjects and all subgroups (all P<0.05). Moreover, systolic blood pressure of subjects in the high sPAP group was higher than that in low and middle sPAP groups (both P<0.05), and diastolic blood pressure of subjects in high sPAP group was higher than that in low sPAP group (P<0.05). The serum levels of OPN were increased in total cohort(27.9 (22.5,34.0) μg/L vs. 25.6 (18.4, 33.1) μg/L, P<0.05)， and high sPAP group (P<0.05), whereas no differences were found in serum SOD and MDA levels among groups. Furthermore, the serum level of OPN in high sPAP group was higher than that in low sPAP group at high altitude (P<0.05), and there was a trend for decline in SOD level with increasing sPAP (P>0.05). Results from univariable linear regression analysis showed that the serum levels of OPN (r=0.32, P=0.002) and SOD (r=-0.22，P=0.032) were linearly correlated with sPAP in total cohort after high altitude exposure. Multivariate regression analysis showed that the serum levels of OPN(β=0.310，P=0.002) and SOD (β=-0.199，P=0.043) were independently associated with the levels of sPAP at high altitude. Conclusion: After acute high altitude exposure, the serum level of OPN is positively associated with sPAP, suggesting that OPN may be a novel bio-marker for predicting the increase of pulmonary pressure in response to acute high altitude exposure.
Subject(s)
Adolescent , Adult , Humans , Male , Young Adult , Altitude , Blood Pressure Determination , Osteopontin , Pulmonary Artery , SystoleABSTRACT
Objective To investigate the effects of autophagy on cell migration and apoptosis of endothelial progenitor cells (EPCs) in hypoxic environment.Methods Rats' bone marrow-derived EPCs were isolated by density-gradient centrifugation,identified with double-fluorescent staining method,and then divided into 4 groups:normoxia (hypoxia 0h),hypoxia 1h,hypoxia 3h and hypoxia 6h groups for detecting the effects of hypoxia on EPCs migration and apoptosis.Transwell chambers and flow cytometry were used to detect cell migration and apoptosis respectively,and Western blotting was performed to detect the changes of autophagy-related proteins,including microtubule associated protein 1 light chain 3 (LC3-Ⅱ / Ⅰ) and ubiquitin of p62.To investigate the effects of hypoxic-induced autophagy on EPCs migration and apoptosis,cells were divided into 4 groups:hypoxia 0h,hypoxia 3h,hypoxia 3h+ShAtg7 and ShAtg7 groups,and then to detect again the EPCs migration and apoptosis.Results Compared to hypoxia 0h group,the EPCs migration markedly reduced and apoptosis increased in hypoxic 3h and 6h groups with statistically significant difference (P＜0.05).Western blotting showed the expressions of LC3-Ⅱ / Ⅰ significantly increased and of p62 decreased in EPCs by hypoxic treatment for 3 and 6 hours (P＜0.05),implying the increases of autophagy level.After inhibiting autophagy by silencing Atg7,hypoxia 3h+ShAtg7 group further reduced EPCs migration (P＜0.05) and aggravated apoptosis (P＜0.05) compared with hypoxia 3h group.Conclusion Autophagy may play a cytoprotective role through promoting EPCs migration and decreasing EPCs apoptosis in hypoxic environment.
ABSTRACT
Objective To explore the effect of high altitude exposure and short-term acclimation on the platelet-associated parameters by studying the changes of platelet-associated parameters in healthy young man.Methods Four hundred and sixtytwo young men were recruited from Chengdu (the elevation of 500m) during Jun.2012 to Aug.2013 according to the inclusion and exclusion criteria,of which 193 had been living in Chengdu (plain group),and 269 flew from Chengdu to Lhasa (3700m) in 2 hours,and then 147 of them were exposed in the high altitude for 1 day (acute high altitude exposure group),and another 122 for 7 days (short-term acclimation group).The demographic data were collected and the blood routine and platelet-associated parameters were measured of all the participants,and then the information collected were compared between the 3 groups.Results Compared to the plain group,the platelet count (PLT),platelet distribution width (PDW) and plateletcrit (PCT) reduced and the mean platelet volume (MPV) increased significantly (P＜0.05) in the acute high altitude exposure group;while all the indexes in short-term acclimation group returned to approach the levels in the plain group,but statistical differences still existed in PLT,PDW and PCT (P＜0.05).The platelet activating factor (PAF) and epinephrine (Epi) decreased markedly in acute high altitude exposure group than in plain group (P＜0.05);while in short-term acclimation group,the PAF returned to approach the level in plain group,and the Epi was further down (P＜0.05).In addition,no marked difference of 5-HT level was observed in the 3 groups (P＞0.05).Pearson correlation analysis indicated that high altitude-induced reduction of oxygen saturation (SpO2) was positively related to the changes of PLT.Conclusions Acute high altitude exposure may reduce PLT,PDW and PCT levels,but elevate MPV and enhance the platelet activity.The reduction of SpO2 might be associated with the changes of PLT,PDW and PCT.Platelet-associated parameters may be recovered to normal with a compensatory effect after short-term acclimation.
ABSTRACT
Store-operated calcium entry (SOCE), a major mode of extracellular calcium entry, plays roles in a variety of cell activities. Accumulating evidence indicates that the intracellular calcium ion concentration and calcium signaling are critical for the responses induced by oxidative stress. The present study was designed to investigate the potential effect of SOCE inhibition on H₂O₂-induced apoptosis in endothelial progenitor cells (EPCs), which are the predominant cells involved in endothelial repair. The results showed that H₂O₂-induced EPC apoptosis was reversed by SOCE inhibition induced either using the SOCE antagonist ML-9 or via silencing of stromal interaction molecule 1 (STIM1), a component of SOCE. Furthermore, SOCE inhibition repressed the increases in intracellular reactive oxygen species (ROS) levels and endoplasmic reticulum (ER) stress and ameliorated the mitochondrial dysfunction caused by H₂O₂. Our findings provide evidence that SOCE inhibition exerts a protective effect on EPCs in response to oxidative stress induced by H₂O₂ and may serve as a potential therapeutic strategy against vascular endothelial injury.
Subject(s)
Apoptosis , Calcium Signaling , Calcium , Endoplasmic Reticulum , Endothelial Progenitor Cells , Oxidative Stress , Reactive Oxygen SpeciesABSTRACT
<p><b>OBJECTIVE</b>To investigate the changes of the cardiac hemodynamics after acute high altitude exposure in healthy young males and the relationship with acute mountain sickness(AMS).</p><p><b>METHODS</b>Left ventricular function and oxyhemoglobin saturation (SaO2), heart rate (HR), blood pressure (BP) were measured in 218 healthy young males before and after high altitude exposure within 24 h respectively. According to the lake louise score criteria, the subjects were divided into two groups: acute mountain sickness group (AMS group) and non acute mountain sickness group (non-AMS group).</p><p><b>RESULTS</b>HR, diastolic blood pressure (DBP), mean arterial pressure (MAP), left ventricular ejection fraction (LVEF), stroke volume (SV), stroke index (SI) cardiac output (CO), cardiac index (CI) were significantly increased upon acute high altitude exposure (P < 0.05). Whereas SaO2 and end-systolic volume (ESV) were significantly decreased (P < 0.05). In addition, HR, systolic blood pressure (SBP) and MAP in AMS group were significantly higher than those in non-AMS group (P < 0.05). But stroke index (SI) and end-diastolic volume (EDV) in AMS group were significantly lower than those in non-AMS group (P < 0.05).</p><p><b>CONCLUSION</b>Cardiac function in healthy young males upon acute high altitude exposure was enhanced. EDV, HR and SI might become the indexes of predicting the acute mountain sickness in the future.</p>